Hello...New to the forum. I was working on my 2005 Tahoe . The issue is a code that comes up from the rear air (B0434). The problem is the rear air will not switch from hot to cold. Both lines feeding the rear have hot and cold pumping through them. The door that the hot and cold actuator is connected to moves with no obstruction by hand. The steps I have taken thus far are fixing the suggested part that the Bulletin listed as the cause of the code. The air temp actuator and the auxiliary mode actuator both replaced. All parts are the most current to flash upgrades. I cant get the air to blend from cold to warm. All systems reflashed and then the code fires back. When the diagnostic is hooked in the parameters for all actuators are within range and the system can be used with no trouble. As soon as We release the truck after the flash the code comes back and the sytem goes to full cold in the rear air only. Front air has no issues at all. Really lost at this point...first time I have not had a bulletin repair suggestion fix the issue...i have not had really any issues with my Tahoe but this came out of the blue..We just got out of the summer months and needed warm air in the back..this is when i noticed the problem. i have not performed any recent work as far as electrical or battery. Any help would be great. Thank you!! Matt. Part for aux module was 15832319.